ctrl-r "

Actually ctrl-r reg, where “ is the unnamed register from the last yank or delete.

Why

If you have done a block selection and you want to paste, normally you would have to leave selection mode to this and there fore not be able to edit multiple lines at once.

say you have (below) and what to prepend ‘number’.

number 
one
two
three

Place cursor on ‘number’, yiw to yank inner word. Move to ‘o’ of one. ctrl-v to enter block selection, jj to select ott vertically. Then I to enter insert mode. ctrl-r " . ESC.

number 
number.one
number.two
number.three